Wire finishing apparatus



June 19, 1956 G. J. STEVENS 2,750,853

WIRE FINISHING APPARATUS Original Filed July 25, 1949 2 Sheets-Sheet l /IIB 'lOB

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GEORG E JOHN STEVENS HIS ATTORNEY IIF HE "D June 19, 1956 G. J. STEVENS 2,750,853

WIRE FINISHING APPARATUS Original Filed July 25, 1949 2 Sheets-Sheet 2 IOA HF HF IIE IIA

E E INVENTOR.

GEORGE JOHN STEVENS HIS ATTORNEY United States wnus FINISHING APPARATUS George John Stevens, Baltimore County, Md, assignor to Armco Steel Corporation, a corporation of Ohio 4 Claims. (Ci. 9033) My application for patent is a division of my co-pending application Serial No. 106,705 filed July 25, 1949, and entitled, Wire Finishing Method and Apparatus, now Patent No. 2,638,818, issued May 19, 1953, and the invention relates to metal bar, rod and wire stock and, more particularly, stainless steel and generally similar metals displaying a high degree of hardness.

An object of my invention is to provide apparatus for cold-working and finishing hard metal bar, rod and wire stock which will impart high finish detail to the metal stock with nicely calibrated finished gauge and at uniform finishing pressures, which demands but a small number of mechanical and structural elements, and these simple, rugged and inexpensive in themselves, which displays long useful life in the substantial absence of constant supervision and attendance, and which is characterized by the complete absence of moving parts.

Another object is to provide an apparatus of the general type described wherein all tendency toward chattering of the mechanical parts is effectively suppressed or avoided and unusual shocks are absorbed, wherein heat generation is held at a minimum, and wherein galling of the metal stock due to excessive friction and tendency of the wire to weld momentarily to the cutting edge employed, as well as any tendency of clogging the cutting edge, are effectively avoided, and which apparatus is characterized by the substantial absence of scarring, gouging or tearing of the surface of the wire.

All these, as well as many other highly advantageous objects and advantages attendant upon the practice of my invention will in part be obvious and in part more fully pointed out hereinafter, during the course of the following specification.

My invention accordingly resides in the several parts, elements and features of construction, the scope and application of all of which is more fully set forth in the claims at the end of this specification.

In the several views of the drawings, wherein I have illustrated several embodiments of my invention which I prefer at present,

Figure 1 is a plan view in partial perspective of apparatus illustrating my invention;

Figure 2 is an end view of the apparatus of Figure 1;

Figure 3 is an elevation of a portion of cutting assembly of the apparatus; while Figure 4 discloses, in side elevation, a modified form of the cutting and scraping blade employed in the apparatus of my invention.

Throughout the several views of the drawings like reference characters denote like parts.

T facilitate a more ready understanding of my invention, it may be noted at this point that the art is confronted by the need for imparting a surface finish of high quality to stainless steel in the form of bar, rodand wire stock. In many applications of stainless steel wire for example, eye appeal is a particularly important element such as in the production of refrigerator trays, grills atent O for handling food, and the like. These items have the feature in common that the consumer pays a premium price therefor in order to obtain a device of pleasing appearance, and as insurance against rusting or unsightly corrosion, traceable to microscopic seams or pits wherein food particles or acid might lodge and initiate corrosive etching. Many such articles are formed with a colddrawn finish, and following fabrication, are cleaned and electro-polished to a smooth, lustrous finish. The requirement for these items is quite rigid. Unsightly blemishes occasion instant rejection.

Because of the importance of surface perfection in fabricated products there is required stainless steel bar, rod and wire stock which is substantially free of those defects which are so common to ordinary metal production, and which include, illustratively, seams, minute slivers, pits, laps, imbedded scale and similar imperfections. The presence of these defects has long posed a problem and particularly so in those instances where successive passes are had through dies in a cold-drawing process, wherein no intermediate treatments are employed to smooth the wire or obliterate faults. They are encountered in everday mill practice, and result from myriad causes during hot-rolling particularly, and as well, from mechanical blows during transportation about the mill and in other processing. Added up, the accumulative efiect of this faulting is to render the finished product less attractive than is desirable for the competitive purposes for which it will be employed.

Frequently, the surface defect is so serious as to necessitate discarding the product. Often, instead of metal displaying a highly polished, lustrous and pleasing appearance which readily lends itself to electro-polishing subsequent to fabrication into a mirror finish, there is produced a surface which is streaked, frosty, and dull. Not only is the production of such surface costly, in that special after-treatment is required, such for example as mechanical bufling, but indeed, in the production of certain fabricated articles, involving imparting an intricate shape to the wire, this after-treatment is impractical, and it is impossible to impart the required good appearance to the fabricated wire.

Now in the prior art considerable difficulty has been encountered in imparting a high quality finish to stainless steel bar, rod and wire stock. Although numerous methods are available, none quite meets the problem of simplicity, efiiciency and cheapness required. To illustrate, centerless grinding gives a good surface but this method can be resorted to only in the most specialized instances, because of the cost attendant upon straightening the rods or wire before insertion in the grinding machine. Alternatively, resort must be had to special devices in order to grind the coiled wire. And too, the element of costs attendant upon this grinding technique effectively excludes it from ordinary use. Morever, aside from the element of cost, centerless grinding is so slow and tedious as to preclude its use where high speed is essential.

Similarly, the use of rotating cutting tools is impractical, expensive and time-consuming.

In the production of copper wire there has been employed the technique of scraping or shaving the metal wire, following drawing to approximate size with a slight degree of oversize. This is used as one of the final steps for preparing the wire stock for the application of insulation or coatings, as well as for other special purposes. I find, however, that such processes, while entirely satisfactory for the treatment of soft metal stock of which copper wire is typical, are not entirely satisfactory for the treatment of stainless steel bar, rod and wire stock.

Many reasons contribute to this situation. Illustra- Patented June 19, 1956.

tively, the forces required to pull refractory metal wire stock through the die are considerable, so that it is highly important and essential that careful alignment of the metal stock relative to the die be achieved. Failing this, chattering of the die is encountered, and gouging of the 'wire stock is occasioned. Such treatment is attended by the evolution of a high degree of heat. Moreover, a strong tendency is observed of the stainless steel metal wire stock to gall, i. e., become injured as a result of excessive friction; and as well, it is found that the metal stock will momentarily weld to the cutting edge of the die. This not only spoils the finish of the wire, but effectively avoids the very purpose of the treatment.

Of the various methods tried I find that certain inherent and basic advantages attend upon shaving a very thin layer from the surface of the wire as a final phase in the manufacture thereof. The wire, of course, is left slightly oversize as it is introduced into this step in order to adapt the wire to the shaving technique. The problem still remained as to how to accomplish the foregoing, and this at high speed, without adding excessive costs or extra operations to the production operation. This problem has not been adequately solved prior to my invention.

An important object of my invention, therefore, is to provide means for mechanically treating stainless steel bar, rod and wire stock and generally similar metal stock in a cold-drawing process so as to effectively eliminate the defects attendant upon the occurrence of seams, minute slivers, pits, laps, imbedded scale and similar surface defects and imperfections, and this in rapid and inexpensive manner, without the necessity of straightening the wire prior to or following passage through the treating apparatus; which means is readily applicable, in the substantial absence of skilled operators, for the treatment of metal stock of both small and large size regardless of the cross-sectional configuration thereof; and which will permit the production of a uniformly polished, lustrous surface to which a mirror finish can be readily imparted in the substantial absence of streaked, frosted or dulled portions, which surface effectively precludes the occurrence of rust or unsightly corrosion and effectively avoids the occurrence of microscopic points of attack.

Viewed from its simplest aspect, my invention may be considered as comprising the provision of two or more bladed cutting tools, complemental to each other, disposed in generally opposed relationship, and each being held under a condition of strain by springs or other flexible means. This is desirable so that when the cutting elements encounter undue local and momentary increase in pressure of the metal stock on the cutting edges, they will yield momentarily so that the pressure is automatically relieved. In other words, the spring-imparted force is overcome by the momentarily greater and opposed force imparted by the metal wire. By this means, I effectively avoid the hazard of burning the wire stock as a result of acute momentary friction. At the same time I achieve the happy result of avoiding premature dulling of the cutting surfaces which would otherwise attend, in all probability, upon the cutting die being forced to bite into the metal stock. Moreover, I effectively remove the danger of the freshly-cut metal welding to the cutting tool; and as well, I avoid the creation of a built-up edge on the cutting tool, resulting from buildup of wire metal welded thereon, and which, once formed, displays a detrimental tendency to scar, gall, or mar the shaved wire. Additionally, I eliminate danger of clogging the cutter elements by entrapped chips, and as well, avoid the progressive gumming of the metal as is so commonly attendant upon the treatment of high alloy steels.

And preferably I impart a negative rake to the cutting tool, which I frequently refer to herein as a die. This negative rake provides a scraping action rather than a conventional cutting action; and in my preferred embodiment I elect to use a scraping tool. However, I do not desire to be limited to this cutting technique, but contemplate and seek to encompass by this application both a scraping action, as a preferred embodiment, and a true cutting action, as within the scope of my invention. To this end, I employ the term cutting, as used in connection with the cutting or scraping action of the cutting or scraping tools, in its generic sense, rather than in a more limited sense, except where such definition is clearly inconsistent with the scope and intent of the text hereof.

With the foregoing general disclosure in mind, description will now be made of a specific embodiment of my invention according to Figures 1 and 2, which is particularly adapted for shaving wire of circular cross section. I provide a base plate 10 of heavy metal, preferably of generally circular form, and which is drilled as at 10A, 16A to permit its being bolted to a standard wire-drawing bench. Inasmuch as these wire-drawing benches are conventional in the art, and assume many embodiments, and since the particular shape and construction of bench does not in itself form part of my invention, disclosure thereof is omitted in the drawings, for simplicity and clarity. And on said base plate I provide a series of two or more assemblies for holding cutting tools. Conveniently, these may be four, five, or more in number. In the present embodiment, however, I employ a series of three such assemblies. Accordingly, the three such assemblies, indicated generally at 11., 12, and 13, are provided for holding suitable scraping tools thereon as an essential part thereof.

Considering now, by way of illustration, the assembly 11, this consists of paired metal supports 11A, 11A disposed preferably diametrically opposed to each other, and suitably bolted to the base plate 10 so as to allow a slight. play therebetween. Here, by way of illustration, a portion of the supports 11A, 11A of reduced section (not shown), passes through the base plate 10 and terminates in threaded shank 11B, 11B. Nuts 11C, 11C serve, together with the related shank portions 11B, 11B, to make the respective supports 11A, 11A, loosely secure to the base plate 10.

At the free ends of the supports 11A, 11A, I provide extension members 11D, 11D, formed of suitable metal, of section suflicient to impart substantial rigidity to the assembly. These extensions are disposed at right angles to the length of the support. That is, they extend substantially parallel to the plane of the base plate 10, on an imaginary diameter thereof, and are disposed toward, but terminate short of each other. Thus, these extensions, while pointed toward each other, do not meet, and leave a space surrounding an imaginary line projected axially through the center of the base plate and through the center of the supports. This effectively places the axis of the extensions above the center of the base plate.

These extensions may be made fast in any suitable manner to the supports 11A, 11A. In the preferred embodiment, the extensions 11B, 11B are each provided with a transverse bore, and headed bolts 11E, 11E pass through said bores in extensions 11D, 11D and thread into tapped recesses (not shown) disposed centrally and axially in the free ends of supports 11A, 11A. Suitable lock washers 11F, 11F are disposed about the shafts of the bolts 11E, HE and are interposed between the outermost surface of the extensions 11D, 11D (remote from the base plate 10) and the headed ends 11E, 11E of the bolts. Preferably, although not necessarily, these may be split lock washers.

On the faces 11G, 116 of the extensions 11D, 11D, facing the base plate 10, I provide recesses or inset portions 11H, 11H. As will be seen, these recesses 11H, 11H are slightly bevelled, and taper to a slight angular extent outwardly from the base plate in a direction toward the axis of the wire-supplyingv orifice .lflB'provided centrally of the base plate 10. Moreover, the bevelled'recess 11H 0n the one extension 11D preferably is advanced slightly beyond the bevelled recess on the other extension. And in the region of the recesses 11H, 11H the extensions 11D are drilled as at 11], 111 to receive holddown means such as headed bolts 11K, 11K for the corresponding element 11L, 11L of the cutting tool. These latter elements, by reason of the advance of one bevelled recess beyond the other, are in a somewhat staggered position.

This bevel imparted to the recesses 11H, 11H serves to impart a negative rake to the cutting tool 11L, so that the latter, in use, will give rise to a true scraping, as distinguished from a cutting action. Conveniently, the cutting edge 11M, 11M of the cutting tool 11L, 11L is ground at an approximately 90 angle. This is not mandatory, however, and the angle of cut as just recited may be departed from to a reasonable extent without seriously detrimental effect. The cutting blades or die elements 11L, 11L are formed of highly resistant tool metal, and illustratively, are sufficiently thin to permit flexing where excessive loading is encountered.

As perhaps best seen in Figure 1, the center 11N, 11N of each cutting edge is ground to the shape of a semi-circle, so as to conform closely to and adapt itself to the shape of the wire just being shaved. It may be noted here that the semi-circular recesses 11N, 11N in the cutting dies are provided only where metal stock of circular section is undergoing processing. It is equally feasible, and is within the full contemplation of my invention, as pointed out hereinbefore, to conform the recesses 11N, UN to the shape of the section of the particular metal stock which is undergoing treatment. Thus my invention readily lends itself to the treatment of stock of various configurations; and to accommodate the shaving apparatus to different shapes of bar, rod and wire, it is sufiicient simply to back off the hold-down bolts 11K, 11K from their recesses 111, 11] in the extensions 11D, 11D, and replace the shaving dies, the reverse of the foregoing procedure being employed in order to bring the replacement dies in working position.

So mounted, the paired tools or cutting dies 11L, 11L are disposed on the extension arms in such fixed position that the opposed semi-circular openings 11N, 11N therein nearly meet, and together form a generally circular cutting opening divided in two, with one semi-circular opening being staggered with respect to the other a small amount, say about As has been stated, this opening 11P thus formed preferably should be disposed nearly opposite the center of the base plate 16. Preferably I dispose this opening 11F exactly opposite the corresponding opening 10B in the base plate 19, through which opening 10B the metal stock is supplied.

While I have referred hereinbefore from time to time to cutting tools and to cutting operation, I used this term in its generic sense to encompass both a true cutting action and a true shaving action, all as more fully explained hereinbefore. To this end I employ a tool mounted so as to impart a negative rake thereto, also as explained hereinbefore. In practice, I prefer to rely upon a shaving, as distinguished from a cutting action; it being my observation that superior results are achieved thereby. However, satisfactory results generally attend upon the use of a tool having a positive rake and thus giving rise to a true cutting action.

The spring action of the cutting die elements 11L, 11L ordinarily is suificient to assure adequate force being applied against the metal stock to give proper shaving. This forces the dies 11L, 11L against the metal stock in a direction toward the center line of the cutting aperture, so that they are applied thereagainst with calibrated nicety. The degree of tension to be employed is best dictated by experience, knowledge as to the composition of metal undergoing shaving, the quantity of metal to be removed in a pass through a single set of dies, together with generally similar factors. I find it unnecessary to provide for any substantial degree of movement, my observation disclosing that a very slight relaxation of movement of the die from time to time, this on the order of one thousandth of an inch, will assure a continuous flow of fine chips, preclude built-up pressures, and permit the die to yield slightly upon encountering local thick spots in the metal stock. As soon as the local reverse strains are eliminated, the spring force of the die elements 11L, 11L assures the cutting surfaces being applied against the stock with undiminished pressure.

It will readily be appreciated from the foregoing that important forces will be encountered, tending to force apart the cutting tools 11L, 11L and as well, tending to force the extensions 11D, 11D outwardly at an obtuse angle relative to the supports 11A, 11A. To resist this tendency, I provide studs 11R, 11R disposed one on each side-face of each extension arm 11D, 11D. Thus, there will be two such studs 11R, 11R for each extension arm. The studs 11R on the rightmost extension arm 11D in Figures 1, 2, and 3 each has threaded therein a threaded bolt 118, which extends generally parallel with respect to the extension arms and toward the other support 11A. These bolts extend loosely through suitable openings in the studs 11R, 11R of the left-most extension 11D and protrude therebeyond. A lockdown nut 11T, HT is provided, one on each bolt 115, on the free end thereof.

By threading down this take-up nut 11T on its corresponding bolt until it abuts against the outer face of the corresponding stud 11R (the face thereof which is remote from the corresponding stud 11R of the other extension 111)) I am enabled to lock the two extensions rigidly with respect to each other in that position in which they are most nearly brought into exact alignment. Substantially all tendency of the assembly towards detrimental chattering and vibration due to variation in resistance interposed by the cutting dies to the passage of the wire stock therethrough is effectively suppressed. And, of particular importance, I find that these bolts provide additional elasticity for the shaving die elements 11L, 11L.

The intermediate die assembly indicated generally at 12 and having support arms 12A, 12A and extension arms 12D, 12D is substantially identical with the first-mentioned assembly, indicated generally at 11, with two important differences. Firstly, the supports 12A, 12A, of equal length, are appreciably shorter than the supports 11A, 11A. Preferably, although not necessarily, these supports 12A are two-thirds the length of the supports 11A. This is primarily for the purpose of symmetry and to permit equalizing to a substantial extent the stresses through the wire stock. It is entirely possible, however, without departing from the spirit of my invention, to form the supports 12A, 12A of any desired length. Secondly, the supports 12A, 12A are offset angularly on the base plate 11, relative to the supports; 11A, HA. In this manner the cutting tools 12L, 12L of the assembly are disposed in such manner that the transverse opening 12? between the split die elements is angularly offset with respect to that opening 111 through the cutting elements IIN, MN for reasons which will be developed hereinafter. Again, preferably but not necessarily I offset the supports 12A, 12A relative to the supports 11A, 11A. Finally, I provide a third such cutting assembly indicated generally at 13, 13 which is in exact conformity with the assemblies 11 and 12 except in the two respects that the support arms 13A, 13A thereof are of lengths different from both supports 11A, 11A and 12A, 12A. Preferably, although not necessarily, these supports 13A, 13A are one-third the length of the supports 11A, 11A and onehalf the lengths of the supports 12A, 12A. Secondly, the supports 13A, 13A are angularly off-set on the base plate It 240 with respect to the supports 11A, 11A and 120 relative to the supports 12A, 12A. In this manner the split opening between the adjacent cutting tools 13L, 13L is offset angularly with respect to the opening through the cutting dies 11L, 11L and 12L, 12L.

With the foregoing construction in mind, it will readily be seen that with my new cutting device properly disposed on the wire-drawing bench, the wire to be processed is passed, first through the guide aperture 10B on the base plate 10, then through the opening 13F of the nearest cutting tool, then through the opening MP of the last cutting edge. As a result of disposing the paired cutting elements llL, ML and so on in angular arrangement relative to the periphery of the base plate, those sections of the wire which are not shaved clean in the passage through one such cutting assembly, as for example at the open seam between the elements of the split die, are scraped clean in the passage through the next successive cutter.

As I have stated, I find the standard wire-drawing bench to be an entirely satisfactory means for moving the wire through the apparatus. I find it entirely feasible to combine my scraping or shaving operation with the final pass of the wire stock through a conventional cold-drawing operation. When this technique is resorted to, it is apparent that much manipulation is eliminated, which would be requisite were not the two steps combined into a single procedural phase. Moreover, the added advantage attends upon such practice in that the scraping serves here to remove the products of cold-drawing such as excess lead, lime, or other drawing lubricants.

As illustrative of the operation of my invention, I have employed a coil of type 302 (188 chromium-nickel) stainless steel wire of circular cross section. I shaved the same to a depth of about 0.0005 to 0.002 inch, ernploying my new shaving apparatus. In so doing, I employed a combination of three paired cutting dies, using a conventional drawing bench as a source of power. I fed the wire first through a conventional cold-drawing die, and there reduced the same to a cross sectional diameter slightly in excess of the desired finish size which was 0.25 inch in diameter. As the wire moved from the colddrawing die, I fed the same to the guide opening 108 of my shaving apparatus, and thence through the three shaving dies, finally winding the same around the winding drum on the drawing bench. In the operation described, I employed a drawing speed of fifty feet per minute. However, it is entirely feasible to increase this speed to as much as one hundred feet per minute or more. The average depth of metal removed was about 0.0005 inch.

Upon inspection, it was found that as the wire emerged from my new shaving apparatus, it was uniformly smooth and free of imperfections and as a result, presented a clean, fresh, metallic appearance which was substantially free of seams, slivers, pits, die scratches, or chatter marks. I thereupon cleaned the finished wire of grease and residual drawing compounds by flash-pickling, and then electro-polished the wire stock in glycolic-sulphuric acid solution.

Inspection disclosed the electro-polished surface to be uniformly mirror-like and highly burnished, and in this respect, in sharp contrast with similar wire, cold-drawn at the same time through the same die but not shaved, and which wire stock, so treated, displayed a much duller finish following electro-polishing and one less uniform in quality.

While in the apparatus illustratively described sufficient elasticity is had in the die elements and in the tensioning bolts to assure the desired shaving of the metal stock, it will be understood that where desired, individual springs may be provided for the die element and provision made for adjusting the degree of tension with which the spring elements apply the shaving tools 11L, 11L against the stock. Such an embodiment of my invention is shown in Figure 4 of the drawing. There it will be seen the stiff springs 11V, 11V replace the mid-portions of the bolts 118, 118.

I have found that by imparting flexibility to the cutting tool important advantages are achieved in addition to 8 simply. relieving localized and transitory excess pressure conditions. Illustratively, I effectively eliminate the danger of chattering, and as well, avoid the chatter marks which so commonly attend upon the use of solid or rigidly fixed cutter elements. Moreover, all necessity of straightening or positioning the wire before cutting is removed. Coiled wire may be shaved without necessity of recourse to positioning dies inserted before and after the cutting tool. The flexible and movable character of the cutting edge enables it to follow the wire in its convolutions, bends, or twists, within reasonable limits.

My invention permits the ready shaving of bar, rod or wire stock of any regular cross section, be the same square, hexagonal, poly-faced or of special section. The grinding and conditioning of the two cutting edges to accommodate conventional round or even unconventional shapes, is readily accomplished in essentially the same manner that ordinary form tools are conditioned. The dies may be readily replaced to accommodate for wire stock of different sizes and cross sections. The ordinary draw bench can be readily employed without material adaptation. The shaving apparatus is simple and of low first cost. It can be operated in the absence of skilled labor. It is adapted to high operational speeds. It gives rise to a wire product of superior finish, permitting electro-polishing with entirely favorable results. All these and many other highly practical advantages attend upon the practice of my invention.

The foregoing disclosure is merely illustrative, and it will readily be appreciated that not only will many modifications of the present embodiment suggest themselves to those skilled in the art, but that as well, many embodiments of the basic underlying inventive thought will likewise present themselves. Accordingly, I desire that the foregoing description be considered solely as illustrative, and not by way of limitation.

I claim:

1. Apparatus for mechanically finishing metal stock, comprising, in combination, a centrally-orificed base plate, through which orifice the metal stock is supplied, a multiplicity of cutting elements supported by said base plate symmetrically about the stock and in spaced relation from each other and each with negative rake respecting said stock, and individual spring means associated with each said cutting element for yieldingly urging the cutting element against the stock.

2. Apparatus for mechanically finishing metal stock, comprising, in combination, a centrally-orificed base plate, through which orifice the metal stock is supplied, a series of cutting element assemblies carried on said base plate in spaced relation both to said base plate and to each other, said assemblies each being centrally apertured, said apertures being substantially in the axial prolongation of base-plate aperture, said cutting elements each having a negative rake, and means associated with each said cutting element for yieldingly urging the cutting element in scraping relation to the stock.

3. Apparatus for mechanically finishing metal wire stock, comprising, in combination, a support, a base plate on said support having an orifice therein through which the metal wire stock is supplied, a series of cutter assemblies also mounted on said common support in spaced relation with respect both to each other and to said base plate and substantially coaxial with the latter, and spring means ultimately reacting against said common support and associated one with each said cutter assembly for imparting flexibility to said cutters and for yieldingly and resiliently applying the same against the wire stock.

4. Apparatus for finishing metal stock, comprising in combination, a base plate; a plurality of pairs of supports fast on and extending outwardly therefrom perpendicularly to the arm thereof, the length of each pair of supports being different from that of the other pairs; extension arms disposed one on each support, the extension arms References Cited in the file of this patent of each pair extending towards but terminating short of UNITED STATES PATENTS each other; and ad ustable means for yleldlngly urging together said extension arms; and split cutting dies ggggg j t d th d t '0 ants in st cred rela- 5 I I moun e on 6 Palm ex ensl n 1 agg 2,233,928 Weaver Mar. 4, 1941 tion and with negative rake. 

1. APPARATUS FOR MECHANICALLY FINISHING METAL STOCK, COMPRISING, IN COMBINATION, A CENTRALLY-ORIFICED BASE PLATE, THROUGH WHICH ORIFICE THE METAL STOCK IS SUPPLIED, A MULTIPLICITY OF CUTTING ELEMENTS SUPPORTED BY SAID BASE PLATE SYMMETRICALLY ABOUT THE STOCK AND IN SPACED RELATION FROM EACH OTHER AND EACH WITH NEGATIVE RAKE RESPECTING SAID STOCK, AND INDIVIDUAL SPRING MEANS ASSOCIATED WITH EACH SAID CUTTING ELEMENT FOR YIELDINGLY URGING THE CUTTING ELEMENT AGAINST THE STOCK. 